Java Multirelease POC

This is a proof of concept how to create a jar file containing multiple Java versions. Intent is to demonstrate use of configuration transitions.

Problems

I don't know much about MR jars. Currently the example just adds all classes to a single jar without changing the path or adding moduleinfo.class.

The code uses locally installed JDK8, because there is no remote_jdk8. User should fix the path in WORKSPACE file.

Test

$ bazel build //:binary8+11
$ mkdir tmp
$ cd tmp
$ unzip  ../bazel-bin/binary8+11.jar
$ javap -verbose A.class | grep "major"
  major version: 52
$ javap -verbose B.class | grep "major"
  major version: 55